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United States Patent |
6,065,277
|
Foil, Jr.
|
May 23, 2000
|
Process for producing dyed spun cotton yarns having improved uniformity,
physical properties, and luster and yarns thus produced
Abstract
A process for producing dyed spun cotton yarns having a reduced number of
irregularities and increased luster is described. The process involves
dyeing at least a portion of the cotton fibers which are to form the yarn,
then combing the dyed fibers subsequent to the dyeing process. The dyed
and combed fibers are then optionally blended with fibers having a
visually distinct appearance, and spun into a yarn using conventional
spinning methods. The resulting yarns having a dramatically reduced number
of thick and thin places and improved yarn properties including improved
luster and hand. Furthermore, when the thus-dyed fibers are blended with
differently-colored fibers prior to the combing operation, the resultant
yarns match the visual colors of like-colored yarns produced by
conventional processes, while the color is more intimately blended and the
yarns have a markedly increased uniformity, luster and tenacity. As a
result, fabrics produced from the yarns have a superior appearance with
respect to color blend and luster, and the number of neps and
irregularities are dramatically reduced with respect to those of
conventionally-produced fabrics.
Inventors:
|
Foil, Jr.; Martin Boger (Concord, NC)
|
Assignee:
|
Tuscarora Yarns, Inc. (Mt. Pleasant, NC)
|
Appl. No.:
|
080053 |
Filed:
|
May 15, 1998 |
Current U.S. Class: |
57/2; 19/65A; 19/115R; 19/145; 19/145.7; 57/75; 57/252; 57/408; 57/409 |
Intern'l Class: |
D01H 004/00 |
Field of Search: |
57/252,75,404,408,409,2
19/145,145.7,65 A,115 R,98
|
References Cited
U.S. Patent Documents
1736592 | Nov., 1929 | Gwaltney.
| |
2373191 | Apr., 1945 | Landolt et al. | 8/18.
|
2542314 | Feb., 1951 | de Lacotte | 19/146.
|
2671250 | Mar., 1954 | Fidell | 19/146.
|
2851849 | Sep., 1958 | Merrill.
| |
3604197 | Sep., 1971 | Saidaiji et al. | 57/140.
|
3864902 | Feb., 1975 | Wehling et al. | 57/58.
|
3987615 | Oct., 1976 | Hill | 57/408.
|
3988108 | Oct., 1976 | Segoshu et al. | 58/18.
|
4335185 | Jun., 1982 | Adelman et al. | 428/361.
|
4369213 | Jan., 1983 | Adelman et al. | 427/389.
|
4539806 | Sep., 1985 | Stahlecker | 57/409.
|
4699627 | Oct., 1987 | Bailey | 8/602.
|
4753066 | Jun., 1988 | Briner et al. | 57/409.
|
4773209 | Sep., 1988 | Briner et al. | 57/408.
|
5025533 | Jun., 1991 | Faas et al. | 19/145.
|
5155989 | Oct., 1992 | Frey et al. | 57/327.
|
5331801 | Jul., 1994 | Heifetz | 57/400.
|
Primary Examiner: Stryjewski; William
Attorney, Agent or Firm: Alston & Bird LLP
Claims
That which is claimed:
1. A method of making a heather yarn having improved fiber blending and
luster comprising the steps of:
providing a quantity of dyed cotton fibers having a first color;
providing a quantity of second fibers having a color which is visually
distinct from that of said first fibers;
feeding said first and second fibers to a combing machine and combing said
fibers together, to thereby blend said first and second fibers, remove
noils and align the fibers to thereby form combed stock; and thereafter
spinning said combed stock into a yarn.
2. The method according to claim 1, wherein said step of spinning said
combed stock into a yarn is performed on a ring spinning machine.
3. The method according to claim 1, wherein said step of spinning said
combed stock into a yarn is performed on an open end spinning machine.
4. The method according to claim 1, wherein said step of providing a
quantity of second fibers comprises providing natural cotton fibers.
5. The method according to claim 1, wherein said step of providing a
quantity of dyed cotton fibers comprises providing combed dyed fibers.
6. The method according to claim 1, further comprising the step of combing
the dyed cotton fibers subsequent to dyeing them and prior to feeding and
combing said first and second fibers together.
7. The method according to claim 1, wherein said step of combing the fibers
together is performed so as to remove at least about 17% noils.
8. A method of making a blended color yarn for use in forming a cotton
fabric having at least two visually distinct fiber colors and a reduced
appearance of fiber neps comprising the steps of:
(a) providing fibers of at least two distinct colors;
(b) visually determining which of said at least two distinct colors will
present a dominant visual appearance when the distinctly-colored fibers
are combined;
(c) combing the fibers determined in step (b) to present a dominant visual
appearance, to remove noils and neps therefrom;
(d) combining said at least two distinctly-colored fibers together; and
(e) spinning the fibers into a yarn.
9. The method according to claim 8, wherein said step of combining said at
least two distinctly-colored fibers is performed subsequent to the combing
of the fibers determined in step (b) to present a dominant visual
appearance, and said step of combining comprises combing the fibers
together.
10. The method according to claim 8, wherein said step of spinning the
fibers into a yarn is performed on a ring spinning machine.
11. The method according to claim 8, wherein said step of spinning the
fibers into a yarn is performed on an open end spinning machine.
12. A process for producing colored cotton yarns having improved luster and
a minimal number of neps comprising the steps of:
supplying a quantity of cotton fibers to a dyeing machine;
dyeing said cotton fibers to achieve dyed cotton fibers having a
predetermined color; then
feeding the fibers to a combing machine and combing said dyed cotton fibers
to align the fibers and remove noils therefrom; and
spinning the fibers into a yarn.
13. The method according to claim 12, wherein said step of spinning the
fibers into a yarn is performed by a ring spinning method.
14. The method according to claim 12, wherein said step of spinning the
fibers into a yarn is performed by an open end spinning method.
15. The method according to claim 12, further comprising the step of
blending said dyed cotton fibers with differently-colored fibers prior to
said step of spinning the dyed cotton yarns into a yarn, to thereby form a
multi-colored yarn.
16. The method according to claim 15, wherein said differently-colored
fibers comprise undyed cotton fibers.
17. The method according to claim 15, wherein said differently-colored
fibers comprise synthetic fibers.
18. The method according to claim 12, wherein said step of combing said
dyed cotton fibers is performed using a comb having at least about 1000
teeth per square inch.
19. The method according to claim 18, wherein said step of combing is
performed using a comb having at least about 1400 teeth per square inch.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to a process for spinning cotton yarns.
More specifically, the invention relates to a process for producing dyed
spun cotton yarns having minimal irregularities and increased luster and
tenacity, and the yarns thus produced.
2. Description of the Prior Art
For thousands of years, cotton yarns have been used in the production of
apparel and other goods. In addition to being cost efficient, cotton has
good absorbency, is comfortable to wear, launders well, and tends to be
relatively durable.
Cotton fibers are the hairs which grow on the cotton seeds. Cotton is
harvested when mature, and taken to a cotton gin where the fibers, also
known as cotton lint, are stripped from the seeds. If performed well, the
ginning process minimizes the pick-up of unwanted plant material, while
retaining some of the natural oils on the fibers. The fibers are then
combined and compressed into large bales (generally on the order of about
500 pounds each) and transported for processing.
Because cotton is a natural fiber, it can come in many varying forms. In
addition to their being various types of cotton plants themselves, the
cotton lint produced can be affected by the composition of the soil,
amount of rainfall and sunlight which the plant receives, etc. As a
result, individual fibers can vary in shape, diameter, and in fiber
length, etc., with the longer length fibers being generally preferred for
high quality apparel applications.
Because cotton fibers are hair-like, they also have a tendency to become
entangled with each other during processing. Such thickness variations,
tangles and trash result in irregularities in the yarns which the fibers
are used to produce; it therefore can be desirable to reduce the number of
such variations and tangles during the processing steps prior to yarn
spinning.
As noted above, the cotton fibers are generally provided to a yarn spinning
facility in bale form. These bales are then broken up and trash is removed
from the fibers. This process is commonly referred to as "opening", and
the fibers emerge from the opening process in a loose, fluffy mass.
However, this mass may still include significant amounts of trash and
short and tangled fibers, which need to be removed before the fibers can
be spun into a high quality yarn.
Cotton fibers are therefore typically processed through an operation known
as carding, to remove the undesirable trash, neps (small knots of
entangled fibers that will not usually straighten to a parallel position
during carding), and noils (fibers which are undesirably short). In the
carding machine, the clumps of fiber are contacted with pin-covered
rollers which grab and remove a number of the tangled and short fibers and
trash and align the fibers. The emerging carded stock is generally
condensed to form card sliver.
Where a high degree of yarn uniformity is desired, the card stock can be
further processed through a combing machine. In one common form of combing
operation, a number of ends of card sliver are fed in the form of a lap to
the combing machine. In the combing operation, fine metal wires are used
to clean out a number of remaining short fibers and other impurities. The
combed stock is then generally condensed into what is known as comber
sliver. Because the comber is designed to remove small impurities, it thus
generally results in a loss of a relatively large percentage of the input
fiber material; for example, as much as 17 percent of the input material
can be lost as a result of a typical combing operation. In order to
minimize this loss of material and to prevent damage to the combing
machine, heretofore it has been considered to be critical that the fibers
which are input to the combing machine are in an aligned and trash-free
condition.
Where the production of colored yarns is desired, the cotton fibers are
conventionally carded and then dyed. For the production of colored yarns
having fewer irregularities, manufacturers typically comb the natural
fibers as well. Because dyeing tends to entangle the fibers with each
other and the fibers emerge from the dyeing process in a matted form, it
has heretofore been the industry standard to comb the fibers prior to the
dyeing process, as it has been considered to be necessary that the fiber
stock fed to the dyeing machine was well aligned to prevent the
significant further entanglement of the fibers during the dyeing process.
However, the dyeing process tends to impart tangles and mat the fibers
together, such that subsequent separation of the fibers for spinning
results in the imparting of additional neps and tangles. To avoid this
problem, yarn manufacturers often spin combed natural (i.e., undyed)
cotton fibers with dyed card stock, then label the resulting product as a
combed dyed yarn.
Despite traditional carding and combing operations, the yarns produced by
prior art methods still contain a number of irregularities, such as thick
and thin areas and neps or slubs. Depending on the fabric being produced
by the yarns, the appearance of the neps may or may not present a
significant problem. For example, in some types of fabrics, the neps are
seen to add to the character of the fabric while in others, a nep
appearing within a garment can result in its failing quality inspection
and being classified as a factory second or low quality fabric. The
appearance of neps tends to become a more significant issue in yarns
containing a blend of more than one color of fibers. For example, in grey
yarns made from a mixture of black and white fibers, the appearance of a
black nep can significantly diminish the visual appearance of a fabric
made from the yarns.
Another difficulty encountered in the production of spun cotton yarns which
mix more than one color of fiber is that it is difficult to get a
consistent blend of the colors. As a result, knit fabrics produced from
conventional multi-colored yarns often have what is known as a banding or
window pane effect, in which bands of one of the fiber colors stand out in
the knit fabric.
With the foregoing in mind, it is therefore an object of the present
invention to provide a process for providing dyed spun cotton yarns having
improved uniformity and color consistency. It is also an object of the
present invention to provide a method for making spun yarns having
improved luster, and which can be produced at competitive rates of
production with prior art methods.
SUMMARY OF THE INVENTION
These and other objects are provided by the process of the instant
invention, in which at least a portion of the fibers forming a yarn are
combed subsequent to the fiber dyeing process. As noted above,
conventional wisdom dictates that fiber dyeing is performed subsequent to
any fiber alignment steps such as carding and combing. This is because
dyeing processes are generally wet processes, which have a tendency to
drastically increase fiber entanglement, with the increase in entanglement
correlating with the initial degree of entanglement. For purposes of
illustration, the entanglement is similar to the case of hair washing,
where hair which is initially entangled has a tendency to become
dramatically more entangled when washed, as opposed to hair which is
brushed prior to washing. Thus, one would expect that it would be
physically impractical to comb dyed fibers subsequent to the dyeing
operation, without inflicting tremendous damage to the long fibers and
removing a large percentage of the input fiber. In addition, because of
the matted, hard condition in which the fibers emerge from the dyeing
process, one would expect that conventional combing equipment could not be
used to comb dyed fibers, without damage to and build up of fibers on the
comber.
Surprisingly, however, the instant inventor has discovered that by combing
the fibers subsequent to the dyeing operation, spun yarns having greatly
improved uniformity can be readily and efficiently produced. Furthermore,
it has been found that by blending multiple colors of fibers prior to the
combing operation, yarns having a much greater intimacy of color blend can
be achieved, while not affecting the overall color of the yarn. In
addition, the thus-produced yarns have greatly enhanced luster and
softness, as well as tenacity.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a flowchart illustrating steps taken during the process of the
instant invention; and
FIGS. 2A and 2B, when joined at their respective boken ends, show a table
of Uster Evenness Test results corresponding to Example 1;
FIGS. 3A and 3B, when joined at their respective broken ends, show a table
of Statimat M Single End Test results corresponding to Example 1;
FIGS. 4A and 4B, when joined at their respective broken ends, show a table
of Uster Evenness Test results corresponding to Example 2;
FIGS. 5A and 5B, when joined at their respective broken ends, show a table
of Statimat M Single End Test results corresponding to Example 2;
FIGS. 6A and 6B, when joined at their respective broken ends, show a table
of Uster Evenness Test results corresponding to Example 3;
FIGS. 7A and 7B, when joined at their respective broken ends, show a table
of Statimat M Single End Test results corresponding to Example 3.
DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described more fully hereinafter with
reference to the accompanying drawing, in which a preferred embodiment of
the invention is shown. This invention may, however, be embodied in many
different forms and should not be construed as limited to the embodiments
set forth herein; rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the scope
of the invention to those skilled in the art.
With reference to FIG. 1, bales of cotton fibers are opened in a
conventional manner. The fibers can optionally go through an initial
carding process to provide some alignment at this stage of the process. In
the process according to the instant invention, cotton fibers are dyed to
achieve a predetermined color, using conventional fiber dyeing methods
such as batch dyeing. (For purposes of this application, the term "cotton
fibers" is meant to describe batches of fibers in which a major portion of
the fibers are the seed hairs from the seeds of cotton plants. The batches
may also include other types of fibers conventionally used in combination
with cotton fibers, within the scope of the instant invention.)
The dyed yarns are then carded according to conventional carding methods,
and may go through an initial drawing stage as well, although not
required. The fibers are then combed using commercially available combing
machinery, such as the Saco-Lowell Calif. comber. In a preferred form of
the invention, a combing machine set up with approximately 1420 teeth per
square inch (as opposed to the industry standard of about 1002 teeth per
square inch) has been found to perform well in combing the dyed fibers.
Such a high tooth gauge is particularly surprising, since one would expect
that the tangled state of the fibers which are input to the comber would
necessitate the use of a less aggressive combing arrangement. In addition,
in a preferred form of the process of the invention, the air suction on
the comber is increased from conventional levels to optimize the condition
of the fiber output, and top combs which are in pristine condition are
desirably used. While one would expect such conditions to be too
aggressive even for natural fibers, the inventor has surprisingly
discovered that the combed fibers are in excellent condition and that the
tangled fiber input does not damage the comber, as one might expect. In a
preferred form of the invention, the combing of the dyed fibers is
performed to remove about 21-22% noils (as compared with about 17% noil
removal from a "world class" combing of natural fibers).
In one form of the invention, fibers of two or more colors (one of which
may be the color of the natural cotton fibers in their undyed form and at
least one of which is dyed) are blended together, then all of the fibers
are combed. In this form of the invention, it has surprisingly been found
that the color of yarn which would be expected from conventional yarn
processing methods of like-colored fibers is achieved, while the
individually-colored fibers are more intimately blended together than with
the conventional processing methods, so as to result in a more consistent
color throughout the yarn.
In another form of the invention used to produce mixed-color yarns (e.g.,
heather yarns), the manufacturer determines which of the colors to be
blended in the yarn will be the dominant fiber color. For example, grey
heather yarns generally include about 9% black fibers and the rest
natural-colored fibers. In such yarns, black is the dominant fiber color
and in fabrics produced from the grey heather yarns, the black neps
therefore have a tendency to show up more prominently than the
naturally-colored neps. Therefore, in this embodiment of the invention,
the manufacturer combs the dyed fibers which it has been determined will
present the most dominant visual appearance (i.e., in the example, the
black fibers), such that fewer irregularities exist in that fiber color.
As a result, blended yarns spun from the dominantly-colored dyed combed
fibers and the other colored fibers have a slightly lower overall nep
count as compared with prior art yarns formed from like-colored fibers.
(As will be understood, the reduction in overall nep count will depend
somewhat on the percentage of the fibers forming the yarn which have been
combed subsequent to dyeing. However, by strategically selecting which of
the fiber inputs are to be combed, and by the inventor's development of a
process for combing fibers subsequent to the dyeing process, marked
improvements in yarn quality can be achieved through the use of only a
small percentage of the dyed-then-combed fibers relative to the overall
yarn composition.) Therefore, when the thus-produced yarns are formed into
a piece of fabric, the overall appearance is that of a dramatic reduction
in yarn neps. Thus, with only a minimal processing adjustment, a
surprisingly remarkable increase in fabric quality can be realized. In
addition, the thus-produced yarns have a dramatically reduced coefficient
of variation, a reduced number of thick and thin places, increased
breaking factor, and increased tenacity. Furthermore, the thus-produced
yarns have a readily visible increase in luster, which greatly enhances
the appearance of the yarn. In fact, in many of the yarns, and
particularly those in which a dyed fiber quantity is combed prior to
blending with a second quantity of fibers, and the blended fibers are then
combed together, the resulting yarns are substantially free of visual
irregularities, and fabrics produced from the yarns are substantially free
of neps and visual irregularities. Thus, the instant invention enables the
achievement of dramatic functional as well as aesthetic improvements.
In an alternative form of the invention, fibers are dyed then combed, then
blended with fibers of another color. The blended fibers are then combed
together, and spun into a yarn. The thus-produced yarns have enhanced
luster over that of their conventionally-spun counterparts, and while the
color is substantially the same as that which is achieved by conventional
comb-then-dye methods of spinning blended yarns (as described above), the
colors are significantly more intimately blended. The result is a yarn
having a much lusher appearance than that of conventional yarns. In
addition, the yarns have been found to be much softer, particularly when
spun using ring spinning methods. It is to be noted, however, that fibers
processed according to the instant invention can be formed into yarns
using any conventional method, including but not limited to ring spinning,
open end spinning, and air jet spinning methods. In fact, the fiber
preparation process enables the production of finer-size open end spun
yarns than have heretofore been achievable at commercially acceptable
levels of production, since the improved consistency of the dyed fiber
input results in fewer ends down during the spinning process.
In a particularly preferred method of the invention designed to achieve
virtually nep-less heather yarns, the dyed fibers are combed, blended with
natural fibers, and the blended fibers are combed together. As a result,
the dyed fibers have thus undergone two combing operations. In this way,
extremely high quality, soft yarns are produced which have more intimate
fiber blending.
Because the dyeing process often has a tendency to strip some of the
natural oils from the fibers, it has also been found to be desirable in
some cases to add one or more conventional types of lubricant to the
fibers prior to combing them, particularly where the ginning process has
removed more than an optimal level of the fibers' natural oils. The amount
and types of such lubricants can be readily selected depending on the
particular batch of cotton fibers being processed without undue
experimentation by someone having ordinary skill in the art.
EXAMPLES
A variety of yarns were prepared according to various embodiments of the
instant invention, and the results are outlined below for purposes of
comparison with the physical characteristics of conventionally-produced
yarns. For purposes of description below, the term "scratch combed" is
used to describe the combing of fibers which was performed at a machine
set-up designed to remove approximately 2-4% of the fiber noils. As noted
above, scratch combing is a common level of aggressiveness at which fibers
are combed. Also for purposes of the examples, the term "Process 2
Combing" is intended to describe combing using a more aggressive machine
set-up, to remove about 17% or greater of fiber noils.
In all of the examples, the highest quality 11/8" staple length cotton
fibers were used. Each of the samples was then measured to determine the
average yarn size, and four 400 yard lengths of each yarn sample were
analyzed using a Uster Evenness Tester to determine the coefficient of
variation of each, number of thick and thin places, and the number of neps
(i.e., piece of fiber which breaks and balls up, forming a pill on the
outer surface of the yarn.) It is noted that the terms "thick" and "thin"
places are recognized terms of art detected by the Uster Evenness Tester,
as will be readily appreciated by those having ordinary skill in the art.
The averages of each of these criteria were then calculated.
Elongation, force to break and yarn tenacity were then measured on
twenty-five single ends of each yarn using a Statimat M Single End Tester
in its conventional manner, as will be readily understood by those having
ordinary skill in the art. The gauge length was set at 254 mm, the load
cell at 10 N, the preload was 0.50 cN/tex, and the test speed was 5000
mm/min. Again, the average of each of these measurables was calculated, as
was the break factor for each of the yarns.
Example 1
Samples A, B and C of forest green yarns including 80% dyed fibers and 20%
natural fibers were produced as follows. A twist test was conducted for
each of the yarns to determine the average turns per inch (tpi) and
average twist multiple (tm), as noted below:
A. 18/1 Ne 100% cotton yarns were produced from 80% dyed fibers and 20%
natural fibers which were carded together, but not combed. The yarn had an
average twist of 15.9 tpi and an average twist multiple of 3.8.
B. 18/1 Ne 100% cotton yarns were produced from a blend of 20% natural
fibers which were combed according to Process 2 and 80% dyed (uncombed)
fibers. The yarn had an average twist of 16.2 tpi and an average twist
multiple of 3.9
C. 18/1 Ne 100% cotton yarns were produced from a blend of 80% dyed fibers
and 20% natural fibers which had been combed according to Process 2, with
the blended fibers being combed together according to Process 2. The yarn
had an average twist of 16.2 tpi and an average twist multiple of 3.9.
The results of the measurements of Samples A, B, and C are listed in the
tables labeled as FIGS. 2A, 2B, 3A, and 3B.
As illustrated, the yarns prepared according to the instant invention
(i.e., Sample C) had dramatically reduced numbers of thick and thin
places, as well as a dramatic reduction in the number of neps.
Furthermore, the fiber evenness is dramatically improved, as illustrated
by the significant reduction in the coefficient of variation of the yarns
of Sample C as compared with those of Samples A and B. In addition, the
spread between the highest coefficient of variation and the lowest
coefficient of variation for the product made according to the instant
invention (Sample C) is also substantially smaller than the spread between
the highest and lowest coefficients of variation of the yarns made
according to conventional processes (i.e., Samples A and B.) This
indicates that yarns made according to the instant invention are
consistently more uniform than those which are made according to prior art
methods. Furthermore, the tenacity, the elongation, and the force to break
were substantially improved.
Example 2
Samples D, E and F of dark grey yarns including 50% dyed fibers and 50%
natural fibers were produced as follows. A twist test was conducted for
each of the yarns to determine the average turns per inch (tpi) and
average twist multiple (tm) as noted below:
D. 18/1 Ne 100% cotton yarns were produced from a blend of 50% scratch
combed natural fibers and 50% fibers which were scratch combed, then dyed
black. The thus-prepared fibers were then carded together and spun into a
yarn. The yarn had an average twist of 16.0 tpi and an average twist
multiple of 3.8.
E. 18/1 Ne 100% cotton yarns were produced from 50% natural fibers which
were combed according to Process 2 and 50% fibers which were scratch
combed, then dyed black. The thus-processed fibers were then spun into a
yarn having an average twist of 16.5 tpi and an average twist multiple of
3.9.
F. 18/1 Ne 100% cotton yarns were produced from 50% natural fibers which
were combed according to Process 2 and 50% fibers which were dyed black,
then combed according to Process 2. The fibers were blended and combed
together according to Process 2. The yarn had an average twist of 16.9 tpi
and an average twist multiple of 4.0.
The results of the measurements of Samples D, E and F are listed in the
tables in FIGS. 4A, 4B, 5A, and 5B.
As illustrated, the average coefficient of variation for the yarns made
according to the instant invention (Sample F) was substantially lower than
that for the conventionally produced yarns (Samples D and E), as was the
average number of thick and thin places. For example, the Sample F yarns
had an average of 22 thick places per 400 yards, as compared with 1291 in
the Sample D yarns. Furthermore, the Sample F yarns averaged only a single
thin place per 400 yard length, as compared with 355 for the Sample D
yarns, and the average number of neps for the Sample F yarns was a mere 7
per 400 yard length of yarn. Furthermore, increases in the average break
factor, force to break and tenacity were realized.
Example 3
Samples G, H, I, and J of light grey yarns including 9% black dyed fibers
and 91% natural fibers were produced as follows:
G. 18/1 Ne 100% cotton yarns were produced from 9% fibers scratch combed as
natural, then dyed black and 91% carded natural fibers, with the blended
fibers being carded together prior to spinning. The yarn had an average
twist of 16.6 tpi and an average twist multiple of 3.9.
H. 18/1 Ne 100% cotton yarns were produced from a blend of 9% fibers which
were dyed black, then combed according to Process 2 and 91% natural
uncombed fiber stock. The yarn had an average twist of 16.1 tpi and an
average twist multiple of 3.7.
I. 18/1 Ne 100% cotton yarns were produced from 9% fibers which were dyed
black, then combed according to Process 2. The dyed combed fibers were
blended with 91% natural fibers which had also been combed according to
Process 2, and then the blend was combed together according to Process 2.
The yarn had an average twist of 16.7 tpi and an average twist multiple of
3.9.
J. 18/1 Ne 100% cotton yarns were produced from 9% fibers which were dyed
black, then combed according to Process 2 and 91% carded natural fibers,
and the blended fibers were then combed together according to Process 2.
The yarn had an average twist of 15.8 tpi and an average twist multiple of
3.8.
The results of the measurements of Samples G, H, I and J are listed in the
tables in FIGS. 6A, 6B, 7A, and 7B.
As indicated in the tables, the yarns made according to the instant
invention (i.e., Samples H, I, and J) had lower coefficients of variation
(particularly those of Samples I and J, where the blend including the dyed
fiber component was combed together.) As indicated, the average number of
thick and thin places in Samples I and J was reduced to zero. Furthermore,
as indicated by a comparison of Samples G and H, the combing of the dyed
fibers after the dyeing process rather than before it produced dramatic
reductions in the number of thin and thick places as well as the number of
neps.
Thus, yarns made according to the instant invention were found to be more
consistently uniform and had reduced thick and thin regions, as well as
reduced number of neps. Because the neps are generally readily visible
when the yarn is knit or otherwise formed into a fabric, the reduction in
neps achieved by the instant invention results in the ability to produce
higher quality fabrics with dramatically fewer neps. In addition, the
yarns produced according to the instant invention had improved luster,
with the blending of the fiber colors being more intimate throughout the
yarn. Furthermore, the yarns were stronger than those produced by prior
art methods (as illustrated by the increase in force required for break),
and the yarns were more consistent in strength, as illustrated by the
smaller spread between the highest and lowest forces required for break of
the yarn.
Many modifications and other embodiments of the invention will come to mind
to one skilled in the art to which this invention pertains having the
benefit of the teachings presented in the foregoing descriptions and the
associated drawing. Therefore, it is to be understood that the invention
is not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included within the
scope of the appended claims. Although specific terms are employed herein,
they are used in a generic and descriptive sense only and not for purposes
of limitation.
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